Propeller



June 11943. J. AKlNs PROPELLER Filed may .27, 1942 Patented June 1, 1943 PROPELLER Jake Akins, Statesboro, Ga., .assigner of one-half to Alfred A. Dorman, Statesboro, Ga.

Application May ,27, 1942, Serial No. 444,728

(Cl. 11S-42) 4 Claims.

This invention relates to propellers for ships, boats and analogous water craft, and 4an object of the same is to provide a propeller of the screw type which is capable of quick acceleration and high speeds. More particularly, the invention is concerned with a propeller for water craft utilizing a rotor in the form of a screw and a coacting stator in the form of a casing mounting the screw, the parts being constructed and arranged to coact in attaining improved results over prior known propellers of this general type.

Another object of the invention is to provide a propeller for water craft which will deliver maximum propulsion from a relatively small unit, or a propeller unit or assembly which may be made light in weight and occupy a minimum of space and yet at the same time be capable of producing the required propulsion for a relatively wide range of sizes of boats.

Another object is to provide a propeller for ships, boats and analogous water craft which may be :constructed in the form of a compact unit and readily mounted and demounted with a minimum of time and labor.

A further object is to generally improve propellers of the screw and casing type.

The foregoing and other objects and advantages will become apparent in View of the following description taken in conjunction with the drawing, wherein:

Fig. 1 is a central longitudinal section o f `a propeller unit in accordance with the invention;

Fig. 2, an enlarged fragmentary section Of the propeller screw;

Fig. ,3, a view in section and side elevation of the stern portion of a boat showing the preferred manner of mounting the propeller;

Fig. 4, a substantially vertical section through one `of the mounting tubes; and,

Fig. 5, a detailed View of the contiguous ends of the propeller andpower shaft, particularly i1- lustrating a preferred type vof coupling joint,

Referring tothe drawing detail, the propeller proper comprises a rotor of the screw vtype generally indicated at Illwhich is mountedin a 'stator in the form of an elongated tubular casing II which tapers from its enlarged inlet to ,its reduced discharge end. The rotor I0 is also tapered 'from its front toward its rear end to conformto the casing ,-I I.y

'Ihe blade of the screw is indicated at |12` and it will be noted that `the outer edge .of the blade is flanged as at I3, note particularly Fig. '2, with the flange extending rearwardly or in the direction pf propulsion. The flangels in conjunction with I6 and I6 depending from a plate I'I.

brackets I6 and I6 are also rigidly secured to the Working or active face of the blade provides a cupping action which increases the power stroke or propulsion action of the screw per turn of the latter. This clearance between the flange I3 and the inner wall of the casing II should be such as to result in a minimum slippage or leakage of water past the blade, the outer extended surface of the fiange serving to reduce `this loss. Furthermore, the leading edge I3' of the ange is preferably tapered or feathered inwardly toward the active face of the blade so as to deflect the water against said face, thereby reducing the slippage pressure between the flange and the easing.

The casing II may be made of a suitable noncorrosive material such as heavy gauge sheet metal, a bronze casting or the like, the thickness of the casing depending upon the size of the installation or `propeller unit and power requirements. Also, the casing should be constructed with a View toward shielding the screw Afrom damage by contact with rocks and the like. The taper of the casing follows the `taper of the screw and may be of Varying degrees. A gentle taper such as that illustrated in the drawing has given satisfactory results. If the taper is increased, the power .requirements will be correspondingly increased, While on the other hand, there will be an increase in propulsion within .certain practical limits.

The screw blades I2 may be cast integrally with or secured to propeller shaft I4, which projects from `opposite ends of the casing and is mounted in bearings I5 and I5' carried by hanger brackets The the casing, as by welding at the point I8, to insure a rigid and non-displaceable mounting of the screw with respect to the casing. This is an important feature, since the screw is thereby better protected from damage and a reduced clearance between the 4iiange I 3 and casing is permitted.

The screw blade I2 preferably starts a short distance inwardly from the -front of the casing and projects-beyond the rearof thecasing a like distance so that Vthe water will enter the casing before being caught by the screw and will like-v wise be expelled fully from the rear. end of the e casing. The turns of the screw should be such as to balance the propeller.

The propeller unit has been-devised with a view toward enabling quick mounting and demounting operations with -or without taking the boat or ship from the water. Accordingly, the supporting and mounting plate II is provided with upwardly projected stud bolts I9, I9', and the bottom of the boat in rear of the power take-olf has secured thereon a mounting plate 20, note Figs. 3 and 4, which is drilled or formed with holes 2I which register with holes formed in the ships bottom. Tubes 22 are threaded into the holes in the ships bottom in registry with the holes 2| in the plate 20, said tubes being of a height somewhat greater than the length of the studs I9, I9. Sealing caps 23 are preferably applied over the upper open ends of the tubes 22.

The front extremity of the propeller shaft I4 f terminates in a flattened coupling end 24 adapted to engage in a coupling slot 25 formed in the outwardly projecting end of power shaft 26.

The mounting operation may be carried out as follows: i

Assuming the ship or boat is floating o1- in water, the propeller unit may be carried beneath the boat by a suitable float or by o-ther means such as suitable guides manipulated from small boats on opposite sides of the stern of the ship and moved to a point where the bolts I9, I 9 register with the openings 2| in the plate 20 and which are sealed by the capped tubes22. When these bolts register with the tubes 22, they move upwardly therethrough and into the tubes 22 until sealing gaskets 21 seat against the plate 20, thereby sealing the holes 2| from entrance of water, whereupon the caps 23 may be removed and the bolts I9 anchored or secured in place by applying nuts 28. After the bolts I9, I9 have been tightened down, the caps 23 may be applied, providing in conjunction with gaskets 2l a double seal against entrance of water or moisture. v When the bolts I9 register with the openings 2I and the propeller unit rises, the powerfshaft 26 should be turned by hand until coupling slot V25 registers with the flattened coupling .end 24 of the screw shaft I4, whereupon-'the shafts I4 and 26 become coupled together ready for operation. In this manner, the unit can be mounted in a relatively short time. .In fact, experience has demonstrated that with a few men and suitableequipment at hand, propeller units can be substituted ink an unusually short timev either while the boat is in water. or in dry dock.

While no attempt has been made herein to einl plain the theory of operation of .the propeller, yet tests indicate that quick acceleration and high vspeeds `are outstanding features of advan.

pick-up is outstanding.

Y The casing should be made suihciently VruggedV to guard against damage by Vcontact-with rocks or other objects, but the fact that the propeller assembly including the screw andv casing withits mounting plate are held together as a rigid unit.

contributes'materially to the stability and ruggedness of the unit. Furthermore, only arelatively small unit may be necessary for different sizes of boats within a practical range, but here again the size depends upon the acceleration or leakage between the blade and casing, and ifsuiiicent power is availaable, the acceleration or' and speed requirements. As far as the powerv 75 peak is concerned, this is obviously governed to a large extent by the size of the screw, since if the screw is relatively small, the inertia is correspondingly reduced.

It is to be understood that certain limited changes in construction and design of the improved propeller unit may be adopted without departing from the spirit or scope or the invention as defined by the appended claims.

What is clamed is:

1. A propeller for boats, ships and the like cornprising a casing which tapers from the front to the rear end thereof, a rotor mounted in said casing including a shaft provided with a spiral blade which follows the taper of said casing, a mounting plate having one or more mounting bolts or studs projecting upwardly therefrom, means connecting the casing to said mounting plate, a coacting mounting plate secured on the bottom of the boat and having one or more hollow tubes projecting upwardly therefrom through said bottom to the interior of the boat, said tubes being adapted to receive said bolts, and means whereby said bolts may be locked to said tubes.

2. A propeller for boats, ships and the like comprising a casing which tapers from the front to the rear end thereof, a rotor mounted in said casing including a shaft provided with a spiral blade which follows the taper of said casing, a mounting plate having one or more mounting bolts or studs projecting upwardly therefrom, means connecting the casing to saidrnounting plate, a 'coacting mounting plate secured on the bottom of 4the boat and having one or more hollow tubes projecting upwardly therefrom through said bottom to the interior of the boat, said tubesbeing adapted to receive said bolts, means whereby said bolts may be lockedr to said tubes, and sealing caps removably secured on the upper ends of said tubes.

3. A propeller assembly for boats, ships and like water craft, comprising a casing, a rotor mounted in said casing and including a shaft having a spiral blade thereon, a mounting plate having frontand rear bearing brackets depending therefrom, said shaft projecting beyond the front and rear ends of the casing, bearings carried by said brackets in which said shaft is journaled, said mounting plate beingl provided withupwardly-projecting mounting? bolts `o r studs having sealing gaskets at the-bases thereof, a

mounting plate secured on the bottom of theboat and adapted to coact with said first-named plate, said second-named mounted plate beingprovided with openings and the -bottom of the ship or boat overlying said"` plate having'tubes" projected therethrough in vregistration with' saidopenings, said bolts being adapted to register with said openings and project- *upwardly into said tubes, means securing the bolts in place in the tubes with said'sealing gaskets sealing saidv open' ings, andA sealing caps disposed over said tubes to doublyseal against leakage of Vwater therethrough...v f H "f 4. in. combination-witha-'siiip orboat having a power shaft-projecting outwardlythrough 'the bottom' thereof -a= 'propeller unit 'comprising a casin'g,-a rotor mounted in'said casingand i'n'' cluding a propeller shaft having la spiral bladel thereon, a mounting plate having front an'drearbearing brackets depending therefrom; said shaft projecting beyond theA front'a'nd' rear.' ends ofthe i casing,bea`rings carriedby saidbracketsin .which said' propeller sha-ft isi journaledpsaid mounting plate being 'provided with upwardly-projecting.,

being adapted to register with said openings and project upwardly into said tubes, said power shaft and said propeller shaft being provided with coacting coupling ends adapted to register one with the other when said bolts register with said openings and move upwardly into said tubes.

JAKE AKINS. 

